Wire Buddy is an electrician's tool for calculating wire size, conduit size, transformers, over current protection, and ground wire size.  It also lists NEMA enclosure classifications, and across the line starter sizes. 
After entering information like full load amps, insulation type, number of conductors in the conduit and ambient temperature, Wire Buddy will calculate the AWG size needed for installation.
After entering information like conduit type and insulation type, you can drag and drop the number and size of conductors so Wire Buddy can calculate the minimum conduit size.
The Option menu has DIP switches allowing you to set defaults like minimize when not in use, load during boot,  and sound control.
* Please note that there are some unresolved issues with Microsoft Vista & Win 7  at this time. *
Minimum requirements:
Win 98 or greater.  Win NT SR 4 or greater.
800 by 600 pixel resolution or greater.
True Color (16 bit) or greater.
Sound card is recommended but not required.